A top World Health Organization official says a recent string of human bird flu cases from the Middle East to Asia is a new warning of the threat the virus still poses.

Keiji Fukada, coordinator of the global influenza program at the W.H.O. in Geneva, told Reuters news agency Friday, however, that there were still no cases of human-to-human transmissions of the virus.

Fukada said that even in hard-hit Indonesia, which has seen the largest number of deaths from bird flu in the world, there were no cases of human transmission.

Fukada said the increase in cases was most likely part of bird flu's seasonal pattern of worsening in winter months in the northern hemisphere.

On Thursday, hospital officials in Indonesia say the virus claimed another victim there when a 37-year-old woman died of bird flu in the Indonesian capital of Jakarta. Her death raises the country's death toll from the disease to 59.

In late December, three members of a family in Egypt died from bird flu.

Meanwhile in Japan, officials ordered a nationwide inspection of poultry farms after preliminary tests showed that 750 chickens from a farm in southern Japan died of bird flu.

Officials say that final results for the suspected outbreak at the farm in Miyazaki Prefecture could be available as early as Saturday. The farm feeds about 10,000 chickens.

Also on Thursday, health officials in South Korea said a person there has contracted bird flu but has no symptoms of the disease.

Officials in Seoul say the person there was infected during an outbreak of the potentially deadly H5N1 strain that hit poultry farms late last year. The H5N1 strain of bird flu has killed more than 150 people worldwide over the past three years -- none in Japan or South Korea.